How to build better soil

Your soil is alive and teeming with microorganisms. Plants need these microbes to break down nutrients.

Feed the soil, not the plants. Microbes eat organic material such as dead leaves, compost, worm castings and manure. In turn, they process this food into water-soluble nutrients that plants absorb through their roots.

Microbes need to breathe. To operate efficiently, microbes require tiny pockets of air in soil. If the ground is constantly saturated, they drown. Anaerobic (bad) bacteria, which can survive without air, take over and produce alcohol — and plant roots rot.

Soil has structure; don’t rip it up. Repeated tilling and churning collapses the soil structure, contributing to the formation of hardpan, an impenetrable layer of clay. By treating soil with tenderness, air pockets are not disturbed. Instead, layer organic material on top; microbes will come up to get it.

Soil has texture. That texture comes from the mix of gritty sand, smooth silt and sticky clay. Knowing how much of each ingredient is the key to understanding how that soil will perform.

Test your soil before adding amendments. Know your soil’s pH — its acidity or alkalinity. Inexpensive pH test kits are available at nurseries and home-improvement centers. The lower the number, the more acidic the soil; higher numbers are more alkaline. Most plants prefer “neutral” soil — 6.5 to 7.0 on the pH scale. Acid-loving plants such as camellias and azaleas prefer a pH of 5.0 to 6.0. Never go to extremes on the scale. Other basic soil tests measure macronutrients — nitrogen, phosphate and potassium — that are the primary building blocks for plant growth. More extensive testing will measure secondary nutrients — calcium, magnesium and sulfur — and micronutrients including iron, copper, boron and zinc. These other nutrients act like vitamins for plants, promoting health and strong growth, but too much can be fatal.

Building good soil takes time. Don’t expect overnight results. When making adjustments, take baby steps.